I know that answering an old question will bring it back to front on the SO site.

Nevertheless I am not aware if there already is (but I think it would be important to have) some kind of policy for bringing questions back to top in a regular way, in order to avoid starvation for old ones.

Some good questions may have been asked while experts of related topics were not active, or in really unlucky time periods and have not received the amount of attention they deserved.

Of course any kind of implemented policy for old questions revival shouldn't draw too much attention away from new and hot questions.

A possible way of doing it could be to assign each question a hotness rate, that decreases with time but is busted up once in a while, or if someone answers the question (how is already happening).